Usually, especially in newer systems, the CPU is by far the single most costly item inside the case. In my Intel-based 3.2-GHz system, for example, the CPU alone accounts for over half the total system cost. Clearly, needlessly toasting a CPU would be an expensive mistake, so you need a way to safely monitor what's going on inside your system before, during, and after any cooling-system changes.
Alexander van Kaam's "Motherboard Monitor"--MBM--is an amazing tool that can monitor, record, and respond to an enormous array of conditions, including the temperatures of the CPU, case, and hard drive; the speeds of the fans; system voltages; and more. (The exact mix of monitorable items depends on your system.)
Intel specs a 3.2-GHz P4 CPU to be OK at temperatures up to 158 degrees F/70 degrees C. So, for safety, I set MBM to sound an audible alarm and begin to perform an orderly shutdown of my system if the CPU exceeds 150 degrees F/66 degrees C. I similarly set MBM limits and responses for the overall system and hard-drive temperatures so that if, for any reason, the temperatures get out of hand, the system would be able to shut itself off before damage occurred, even if I wasn't present to take immediate action.
ActiveSmart is a more narrowly focused tool, designed to show you the data collected by the SMART ("Self-Monitoring, Analysis, and Reporting Technology") system built into many hard drives. Although the temperature monitoring is redundant if you're already using a tool like MBM, a SMART monitor also looks at many additional measures of hard-drive health, and can give you early warning of an impending failure, even if it's not thermally related.
Just setting up the two monitoring tools led to one immediate and significant result: They showed me that my hard drive was running hot. Normally, at idle, a hard drive generates only a little internal heat, so you'd expect it to be just a few degrees warmer than the air inside the PC's case. But my drive was averaging about 20 degrees F/11 degrees C hotter than the overall case temperature. From that, I could surmise that the hard drive must have been in a dead spot inside the case, with little airflow, so that it could not get rid of its heat.
So, just by installing the monitoring software, I'd already learned something important: I knew that my cooling solution couldn't focus just on noise, but also would have to improve overall circulation inside the case. That way, the hard drive would be cooler and closer to the temperature of the air inside the case. This would extend the life of the hard drive (all solid-state electronics last longer at cooler temperatures) and help keep my data safe.
I couldn't move the hard drive, or the main system fan, so it looked like I'd have to consider adding a second case fan in the vicinity of the drive. But how could I increase the number of fans in the system and still end up with a quieter PC overall?
Well, I'm happy to say it can be done, and the final result was easy, inexpensive--and quiet! But getting there was an adventure in itself, involving a choice of several different types of fans, an experiment with an ultra-quiet--but enormous!--CPU fan and heat sink, and even a look at exotic systems that cool the CPU with water delivered via tiny pumps.
We'll delve into those details in the next column, but for now, let me stress that you can achieve great results with nothing exotic, expensive, or difficult: With just a careful choice of fans and a new heat sink, you can achieve a very high degree of noise reduction, even if you end up adding more fans to the system than you now have (that's what I did). Cool and quiet, just what the doctor ordered!
But for now, in preparation for the next column, I suggest you follow the links above to scope out your own system. Get some temperature- (and maybe SMART-) monitoring tools running, and learn what you're system's parameters are. If nothing else, you'll establish a useful baseline by which to gauge later changes. And maybe, like me, you'll discover that some portion of your system is running hotter than it should be.
And please join in the discussion! What tools do you use to keep track of what's going on inside your PC? What fans, heat sinks, or other devices have you used to keep your PC cool--and quiet! Join in!